It is known in the art relating to linear screw drives to fixedly connect a nut to a moving member in order to move the moving member by the actuation of a screw that drives the nut. With such an arrangement, the rigid connection between the nut and moving member can cause excessive wear on the screw and premature failure of the nut.
In closure panel hemming operations large loads are applied by linear ball screw drives drawing upper and lower dies together to edge hem preformed metal panels. In such operations, there is a need to maximize ball screw life and reduce the failure rate of ball nuts used to move the dies.
Previously, I provided a device for slip-fittably connecting together a ball nut and a moving member moved by the ball nut. The device includes a first connecting member fixedly attached to the ball nut. The first connecting member has first registration elements disposed radially opposite relative to the ball nut. A second connecting member is fixedly attached to the moving member. The second connecting member has cooperative second registration elements disposed radially opposite relative to the ball nut which cooperate with the first radially opposite registration elements.
The first and second registration elements are slip-fittably connectable together and provide indexed registration within predetermined tolerances in the axial, radial and circumferential directions relative to the ball nut.
Other manufacturers utilize gimbals on ball screw drives to effect connections between the fixed one end and free opposite end bearing arrangement to ensure that ball screw force is axial and reduce the potential for side loading the ball screw. However effective these connection solutions may be, allowance for misalignment at the attachment points of a ball screw assembly particularly where a drive mechanism is connected to the ball screw needs to be provided to eliminate side loading and premature failure of the components of the mounting arrangement or system itself.